Wash the mushrooms thoroughly and chop them finely.
Finely chop the onion.
Heat olive oil in a pan and sauté the onion.
When the onion becomes translucent, add the mushrooms and stir-fry.
Season with salt and pepper.
Once the ingredients are cooked, turn off the heat and let them cool.
Put everything in a blender and puree until smooth.
If needed, add extra olive oil to adjust the texture and mix well.